Regional myocardial blood flow in awake dogs

F. R. Cobb, Robert J Bache, J. C. Greenfield

Research output: Contribution to journalArticle

83 Citations (Scopus)

Abstract

The objectives of this study were to test the hypothesis in awake dogs that during control conditions endocardial vessels are maximally dilated and to determine whether variables introduced by general anesthesia and thoracotomy modify distribution of myocardial blood flow or impair capacity for augmentation of flow in response to a coronary vasodilator stimulus. Myocardial blood flow was measured in relatively small, 2 to 3 g, left ventricular epicardial and endocardial samples by using 7 to 10 μm radioisotope labeled microspheres during control conditions and during infusion of adenosine in dosages which produced maximum increases in coronary blood flow. Measurements were made initially in awake resting animals and were repeated after pentobarbital anesthesia, thoracotomy, and pericardiotomy. Blood flow (mean ± SEM) in the epicardium and endocardium, respectively, was 0.75 ± 0.06 and 0.83 ± 0.06 during control conditions and 4.98 ± 0.28 and 4.49 ± 0.27 cm3/min/g during adenosine. These data demonstrate considerable capacity for vasodilation in both myocardial layers and thus refute the hypothesis that endocardial vessels are maximally dilated during control conditions. During control conditions blood flow within epicardial and endocardial layers was essentially homogeneous around the circumference of the left ventricle. In contrast to previous studies in anesthetized animals, however, transmural gradients were present in most regions, i.e., endocardium:epicardium ratio (endo/epi) 1.06 to 1.16. During adenosine, circumferential epicardial flows were homogeneous; however, circumferential endocardial flows were inhomogeneous and increased less than epicardial flows, endo/epi 0.81 to 0.99. Anesthesia, thoracotomy, and pericardiotomy increased epicardial and endocardial flow, mean values 1.08 ± 0.10 and 1.11 ± 0.08 cm3/min/g, respectively. Transmural gradients remained in only papillary muscle regions. Adenosine increased epicardial flow comparably before and after anesthesia. Although adenosine increased endocardial flow 3 to 4 fold after anesthesia, the increase was considerably less than epicardial flow, i.e., endo/epi 0.63 to 0.78.

Original languageEnglish (US)
Pages (from-to)1618-1625
Number of pages8
JournalJournal of Clinical Investigation
Volume53
Issue number6
DOIs
StatePublished - Jan 1 1974

Fingerprint

Regional Blood Flow
Endocardium
Adenosine
Pericardium
Dogs
Thoracotomy
Anesthesia
Pericardiectomy
Papillary Muscles
Pentobarbital
Vasodilator Agents
Microspheres
Vasodilation
Radioisotopes
General Anesthesia
Heart Ventricles

Cite this

Cobb, F. R., Bache, R. J., & Greenfield, J. C. (1974). Regional myocardial blood flow in awake dogs. Journal of Clinical Investigation, 53(6), 1618-1625. https://doi.org/10.1172/JCI107712

Regional myocardial blood flow in awake dogs. / Cobb, F. R.; Bache, Robert J; Greenfield, J. C.

In: Journal of Clinical Investigation, Vol. 53, No. 6, 01.01.1974, p. 1618-1625.

Research output: Contribution to journalArticle

Cobb, FR, Bache, RJ & Greenfield, JC 1974, 'Regional myocardial blood flow in awake dogs' Journal of Clinical Investigation, vol. 53, no. 6, pp. 1618-1625. https://doi.org/10.1172/JCI107712
Cobb, F. R. ; Bache, Robert J ; Greenfield, J. C. / Regional myocardial blood flow in awake dogs. In: Journal of Clinical Investigation. 1974 ; Vol. 53, No. 6. pp. 1618-1625.
@article{4164c413a52643708bb8cb927467c6d5,
title = "Regional myocardial blood flow in awake dogs",
abstract = "The objectives of this study were to test the hypothesis in awake dogs that during control conditions endocardial vessels are maximally dilated and to determine whether variables introduced by general anesthesia and thoracotomy modify distribution of myocardial blood flow or impair capacity for augmentation of flow in response to a coronary vasodilator stimulus. Myocardial blood flow was measured in relatively small, 2 to 3 g, left ventricular epicardial and endocardial samples by using 7 to 10 μm radioisotope labeled microspheres during control conditions and during infusion of adenosine in dosages which produced maximum increases in coronary blood flow. Measurements were made initially in awake resting animals and were repeated after pentobarbital anesthesia, thoracotomy, and pericardiotomy. Blood flow (mean ± SEM) in the epicardium and endocardium, respectively, was 0.75 ± 0.06 and 0.83 ± 0.06 during control conditions and 4.98 ± 0.28 and 4.49 ± 0.27 cm3/min/g during adenosine. These data demonstrate considerable capacity for vasodilation in both myocardial layers and thus refute the hypothesis that endocardial vessels are maximally dilated during control conditions. During control conditions blood flow within epicardial and endocardial layers was essentially homogeneous around the circumference of the left ventricle. In contrast to previous studies in anesthetized animals, however, transmural gradients were present in most regions, i.e., endocardium:epicardium ratio (endo/epi) 1.06 to 1.16. During adenosine, circumferential epicardial flows were homogeneous; however, circumferential endocardial flows were inhomogeneous and increased less than epicardial flows, endo/epi 0.81 to 0.99. Anesthesia, thoracotomy, and pericardiotomy increased epicardial and endocardial flow, mean values 1.08 ± 0.10 and 1.11 ± 0.08 cm3/min/g, respectively. Transmural gradients remained in only papillary muscle regions. Adenosine increased epicardial flow comparably before and after anesthesia. Although adenosine increased endocardial flow 3 to 4 fold after anesthesia, the increase was considerably less than epicardial flow, i.e., endo/epi 0.63 to 0.78.",
author = "Cobb, {F. R.} and Bache, {Robert J} and Greenfield, {J. C.}",
year = "1974",
month = "1",
day = "1",
doi = "10.1172/JCI107712",
language = "English (US)",
volume = "53",
pages = "1618--1625",
journal = "Journal of Clinical Investigation",
issn = "0021-9738",
publisher = "The American Society for Clinical Investigation",
number = "6",

}

TY - JOUR

T1 - Regional myocardial blood flow in awake dogs

AU - Cobb, F. R.

AU - Bache, Robert J

AU - Greenfield, J. C.

PY - 1974/1/1

Y1 - 1974/1/1

N2 - The objectives of this study were to test the hypothesis in awake dogs that during control conditions endocardial vessels are maximally dilated and to determine whether variables introduced by general anesthesia and thoracotomy modify distribution of myocardial blood flow or impair capacity for augmentation of flow in response to a coronary vasodilator stimulus. Myocardial blood flow was measured in relatively small, 2 to 3 g, left ventricular epicardial and endocardial samples by using 7 to 10 μm radioisotope labeled microspheres during control conditions and during infusion of adenosine in dosages which produced maximum increases in coronary blood flow. Measurements were made initially in awake resting animals and were repeated after pentobarbital anesthesia, thoracotomy, and pericardiotomy. Blood flow (mean ± SEM) in the epicardium and endocardium, respectively, was 0.75 ± 0.06 and 0.83 ± 0.06 during control conditions and 4.98 ± 0.28 and 4.49 ± 0.27 cm3/min/g during adenosine. These data demonstrate considerable capacity for vasodilation in both myocardial layers and thus refute the hypothesis that endocardial vessels are maximally dilated during control conditions. During control conditions blood flow within epicardial and endocardial layers was essentially homogeneous around the circumference of the left ventricle. In contrast to previous studies in anesthetized animals, however, transmural gradients were present in most regions, i.e., endocardium:epicardium ratio (endo/epi) 1.06 to 1.16. During adenosine, circumferential epicardial flows were homogeneous; however, circumferential endocardial flows were inhomogeneous and increased less than epicardial flows, endo/epi 0.81 to 0.99. Anesthesia, thoracotomy, and pericardiotomy increased epicardial and endocardial flow, mean values 1.08 ± 0.10 and 1.11 ± 0.08 cm3/min/g, respectively. Transmural gradients remained in only papillary muscle regions. Adenosine increased epicardial flow comparably before and after anesthesia. Although adenosine increased endocardial flow 3 to 4 fold after anesthesia, the increase was considerably less than epicardial flow, i.e., endo/epi 0.63 to 0.78.

AB - The objectives of this study were to test the hypothesis in awake dogs that during control conditions endocardial vessels are maximally dilated and to determine whether variables introduced by general anesthesia and thoracotomy modify distribution of myocardial blood flow or impair capacity for augmentation of flow in response to a coronary vasodilator stimulus. Myocardial blood flow was measured in relatively small, 2 to 3 g, left ventricular epicardial and endocardial samples by using 7 to 10 μm radioisotope labeled microspheres during control conditions and during infusion of adenosine in dosages which produced maximum increases in coronary blood flow. Measurements were made initially in awake resting animals and were repeated after pentobarbital anesthesia, thoracotomy, and pericardiotomy. Blood flow (mean ± SEM) in the epicardium and endocardium, respectively, was 0.75 ± 0.06 and 0.83 ± 0.06 during control conditions and 4.98 ± 0.28 and 4.49 ± 0.27 cm3/min/g during adenosine. These data demonstrate considerable capacity for vasodilation in both myocardial layers and thus refute the hypothesis that endocardial vessels are maximally dilated during control conditions. During control conditions blood flow within epicardial and endocardial layers was essentially homogeneous around the circumference of the left ventricle. In contrast to previous studies in anesthetized animals, however, transmural gradients were present in most regions, i.e., endocardium:epicardium ratio (endo/epi) 1.06 to 1.16. During adenosine, circumferential epicardial flows were homogeneous; however, circumferential endocardial flows were inhomogeneous and increased less than epicardial flows, endo/epi 0.81 to 0.99. Anesthesia, thoracotomy, and pericardiotomy increased epicardial and endocardial flow, mean values 1.08 ± 0.10 and 1.11 ± 0.08 cm3/min/g, respectively. Transmural gradients remained in only papillary muscle regions. Adenosine increased epicardial flow comparably before and after anesthesia. Although adenosine increased endocardial flow 3 to 4 fold after anesthesia, the increase was considerably less than epicardial flow, i.e., endo/epi 0.63 to 0.78.

UR - http://www.scopus.com/inward/record.url?scp=0016146728&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0016146728&partnerID=8YFLogxK

U2 - 10.1172/JCI107712

DO - 10.1172/JCI107712

M3 - Article

VL - 53

SP - 1618

EP - 1625

JO - Journal of Clinical Investigation

JF - Journal of Clinical Investigation

SN - 0021-9738

IS - 6

ER -